This shared instrument grant entitled "Peptide/protein analysis facility" is a request from the Joslin Diabetes Center for funds to purchase equipment to carry out protein and peptide composition and sequence analysis and purification. The Joslin is a combined research institute and patient care facility dedicated to the understanding and treatment of diabetes and related disorders. Research interests are broad, ranging from basic biochemical and molecular mechanisms, to the development of treatments for diabetes and its complications. In recent years, the scope of protein sequence analysis has changed from the aim of determining the complete primary structure of a protein by sequence analysis of peptides, to being an essential component towards an integrated protein data base, summarizing the structural, functional and clinical information from each separated protein. Many current and future NIH supported projects conducted by investigators at the Joslin as well as our close collaborators at other Harvard institutes have evolved to the point where protein purification and primary sequence analysis is absolutely necessary. A recurrent theme in many proposals emphasizes the need for a protein purification and sequencing facility which places top priority on projects focusing on diabetes related questions so that relevant cloning projects and structure/function studies can move forward in a timely way. The proposed "Peptide/protein analysis facility" will complement the recently established a peptide synthesis facility at the Joslin. All synthetic peptides from routine syntheses will be analyzed for composition, and products of more complex syntheses will be analyzed for composition, and products of more complex syntheses will be sequenced as well. Examples of additional projects in which protein sequence analyses are essential include: (1) the analysis of protein antigens on islet cells that are responsible for the development of diabetes; (2) mapping the 3-dimensional insulin binding pocket of the insulin receptor; (3) identification of serine, threonine and tyrosine phosphorylation sites in the insulin receptor and other proteins that are important for biological signal transmission and regulation. Moreover, the facility is essential for the identification, immunological analysis and cloning of (1) endopeptidases responsible for processing proinsulin, (2) substrates of the insulin and insulin-like growth factor I receptor kinase, (3) phosphotyrosine phosphatases which play a role in the regulation of insulin receptor signal transmission, (4) activin and inhibin receptors in the pituitary gland and (5) DNA binding proteins and transcription factors. These are examples of the projects currently underway that will utilize the protein analysis/sequencing facility at the Joslin Diabetes Center. We foresee a very substantial and increasing need for this facility as the Center continues to grow.